Good idea to at least draw. It feels better to me than computer generated because moving hand on paper helps ideas develop better. May have to do with how slowly I work a cad program. Clay is good too, but mainly when it models a small part of the piece I haven't done before or have done too few times to be absolutely comfortable.
All of the thinking, drawing, figuring best order of process, has never resulted in a finished piece that is exactly the embodiment of my planning. If I stumble on an improvement as I go, I'm not handcuffed to what I've generated on paper. What happens equally often is that the execution is a little lacking. It's a hand made thing. It's nice to see the tracks. They're an important part of the story.